Apparatus and method for multi-purpose setup planning for sheet metal bending operations

• US 6,233,538 B1
• Filed: 09/11/1997
• Issued: 05/15/2001
• Est. Priority Date: 09/11/1997
• Status: Expired due to Term

• Current Assignee: Amada America, Inc. (Amada Company Limited), Amada Company Limited
• Original Assignee: Amada America, Inc. (Amada Company Limited)
• Inventors: Gupta, Satyandra Kumar, Bourne, David Alan
• Primary Examiner(s): Teska, Kevin J.
• Assistant Examiner(s): JONES, HUGH M
• Application Number:
  US08/927,291
• Time in Patent Office: 1,342 Days
• Field of Search: 395/500.28, 395/500.27, 703/6-7
• US Class Current: 703/6
• CPC Class Codes: B21D 5/02 on press brakes without making use of clamping means
• CPC Class Codes: B25J 9/1666 Avoiding collision or forbidden zones
• CPC Class Codes: G05B 19/4097 characterised by using design data to control NC machines, e.g. CAD/CAM G05B19/4093 takes precedence
• CPC Class Codes: G05B 2219/40054 Supply sheet to bending machine
• CPC Class Codes: G05B 2219/40476 Collision, planning for collision free path
• CPC Class Codes: G05B 2219/40517 Constraint motion planning, variational dynamic programming
• CPC Class Codes: G05B 2219/40628 Progressive constraints

Abstract

A setup planning technique is provided in which a family of parts to be manufactured is identified, and the setup constraints imposed by the various bending operations in the part family are determined. The setup constraints may define or describe spatial constraints on the sizes and locations of various tooling stages in the setup. After identifying setup constraints, setup plans are generated that satisfy all setup constraints. Any setup plan that satisfies all setup constraints may then be utilized to accommodate every part in the part family. Constraint propagation techniques may be utilized to identify compatible setup constraints and create setup plans. According to the various features and aspects of the invention, dissimilar sheet metal parts can share setups, and the need for extra tooling and fixturing may be minimized. Further, the present invention provides potential savings over state-of-the-art systems, and increases production capability and overall through-put of manufacturing facilities.

Claims

1. A method for multi-part setup planning for operations to be performed by a bending workstation on a plurality of sheet metal parts in accordance with a composite setup plan, said method comprising:

identifying setup constraints for operations to be performed on each of said plurality of parts;

determining, in accordance with the setup constraints that are identified, operations to be performed on said parts that have compatible setup constraints; and

assigning operations that are determined to have compatible constraints to corresponding tooling stages of the bending workstation to develop a composite setup plan for said plurality of parts;

wherein each of the setup constraints comprises a set of setup constraint parameters, said setup constraint parameters defining setup constraints relating to the positioning of the parts in the workstation to perform said operations; and

wherein said setup constraint parameters for each part comprise;

a gap length “

Gr”

on a right side of a bend position of the part, which denotes the distance by which a tooling stage can be extended towards the right side of the bend position;

a gap length “

GI”

on a left side of the bend position of the part, which denotes the distance by which a tooling stage can be extended towards the left side of the bend;

an obstruction length “

Or”

on the right side of the bend position, which denotes a space in which no tooling is allowed on the right side of the bend position;

an obstruction length “

Ol”

on the left side of the bend position;

which denotes a space in which no tooling is allowed on the left side of the bend position;

a safety distance “

Sr”

on the right side of the bend position, which denotes a minimum distance between the bend position and a next tooling stage towards the right side of the bend position; and

a safety distance “

Sl”

on the left side of the bend position, which denotes a minimum distance between the bend position and a next tooling stage towards the left side of the bend position.

2. A method for multi-part setup planning according to claim 1, wherein said determining includes identifying a set of said operations that have compatible setup constraints by locating tooling stages that can accommodate each operation within said set of operations.

3. A method for multi-part setup planning according to claim 1, wherein said setup constraint parameters for each part include tooling parameters, at least one of said tooling parameters being defined according to a minimum tooling stage length for each operation that is given by:

4. A method for multi-part setup planning according to claim 1, wherein said setup constraint parameters for each part include tooling parameters, at least one of said tooling parameters being defined according to a maximum allowed tooling stage length for each operation that is given by:

5. A method for multi-part setup planning according to claim 1, wherein said setup constraints are identified in accordance with the following:

6. A method for multi-part setup planning according to claim 1, wherein said identifying includes determining each of the setup constraints based on an intermediate shape of the part and a configuration of the tooling of the bending workstation for each operation.

7. A method for multi-part setup planning according to claim 6, wherein said determining includes providing a geometric model of the intermediate shape of the part and the configuration of the tooling, and calculating part-tool intersection regions to determine setup constraint parameters for each operation.

8. A multi-part setup planning system for generating a composite setup plan for operations to be performed by a bending workstation on a plurality of sheet metal parts, said system comprising:

means for identifying setup constraints for operations to be performed on each of said plurality of parts;

means for determining, in accordance with the setup constraints that are identified by said identifying means, operations to be performed on said parts that have compatible setup constraints; and

means for assigning operations that are determined to have compatible constraints to corresponding tooling stages of the bending workstation to thereby develop a composite setup plan for said plurality of parts;

wherein each of the setup constraints comprise a set of setup constraint parameters, said setup constraint parameters defining setup constraints relating to the positioning of the parts in the workstation to perform said operations; and

wherein said setup constraint parameters for each part comprise;

a gap length “

Gr”

on a right side of a bend position of the part, which denotes the distance by which a tooling stage can be extended towards the right side of the bend position;

a gap length “

Gl”

on a left side of the bend position of the part, which denotes the distance by which a tooling stage can be extended towards the left side of the bend;

an obstruction length “

Or”

on the right side of the bend position, which denotes a space in which no tooling is allowed on the right side of the bend position;

an obstruction length “

Ol”

on the left side of the bend position;

which denotes a space in which no tooling is allowed on the left side of the bend position;

a safety distance “

Sr”

on the right side of the bend position, which denotes a minimum distance between the bend position and a next tooling stage towards the right side of the bend position; and

a safety distance “

Si”

on the left side of the bend position, which denotes a minimum distance between the bend position and a next tooling stage towards the left side of the bend position.

9. A multi-part setup planning system according to claim 8, wherein said determining means comprises means for identifying a set of said operations that have compatible setup constraints by locating tooling stages that can accommodate each operation within said set of operations.

10. A multi-part setup planning system according to claim 8, wherein said setup constraint parameters for each part include tooling parameters, at least one of said tooling parameters being defined according to a minimum tooling stage length for each operation that is given by:

11. A multi-part setup planning system according to claim 8, wherein said setup constraint parameters for each part include tooling parameters, at least one of said tooling parameters being defined according to a maximum allowed tooling stage length for each operation that is given by:

12. A multi-part setup planning system according to claim 10, wherein said setup constraints are identified by said identifying means in accordance with the following:

13. A multi-part setup planning system according to claim 8, wherein said identifying means comprises means for determining each of the setup constraints based on an intermediate shape of the part and a configuration of the tooling of the bending workstation for each operation.

14. A multi-part setup planning system according to claim 13, wherein said means for determining setup constraints comprises means for providing a geometric model of the intermediate shape of the part and the configuration of the tooling, and means for calculating part-tool intersection regions to determine setup constraint parameters for each operation.

15. A multi-part setup planning system according to claim 8, further comprising means for determining a tooling stage arrangement for said bending workstation, said stage arrangement determining means comprising means for identifying required tooling stages of the composite setup plan and means for generating an arrangement of the required tooling stages in the bending workstation to minimize a transfer frequency of said parts between the tooling stages.

16. A method for setup planning for operations to be performed by a workstation in accordance with a shared setup plan, said method comprising:

defining a family of parts;

identifying setup constraints imposed by operations to be performed on each part of said family of parts; and

generating a shared setup plan that satisfies all of the setup constraints that are identified for said family of parts;

said generating comprises;

determining, in accordance with the setup constraints that are identified, operations to be performed on said parts that have compatible setup constraints; and

assigning operations that are determined to have compatible constraints to corresponding tooling stages of the workstation to develop the shared setup plan for said family of parts;

wherein said determining includes identifying a set of said operations that have compatible setup constraints by locating tooling stages that can accommodate each operation within said set of operations;

wherein each of the setup constraints comprises a set of setup constraint parameters, said setup constraint parameters defining setup constraints relating to the positioning of each part in the workstation to perform said operations; and

said setup constraint parameters for each part comprise;

a gap length “

Gr”

on a right side of a bend position of the part, which denotes the distance by which a tooling stage can be extended towards the right side of the bend position;

a gap length “

Gl”

on a left side of the bend position of the part, which denotes the distance by which a tooling stage can be extended towards the left side of the bend;

an obstruction length “

Or”

on the right side of the bend position, which denotes a space in which no tooling is allowed on the right side of the bend position;

an obstruction length “

Ol”

on the left side of the bend position;

which denotes a space in which no tooling is allowed on the left side of the bend position;

a safety distance “

Sr”

on the right side of the bend position, which denotes a minimum distance between the bend position and a next tooling stage towards the right side of the bend position; and

a safety distance “

Sl”

on the left side of the bend position, which denotes a minimum distance between the bend position and a next tooling stage towards the left side of the bend position.

17. A method for setup planning according to claim 16, wherein said setup constraint parameters for each part include tooling parameters, at least one of said tooling parameters being defined according to a minimum tooling stage length for each operation that is given by:

18. A method for setup planning according to claim 16, wherein said setup constraint parameters for each part include tooling parameters, at least one of said tooling parameters being defined according to a maximum allowed tooling stage length for each operation that is given by:

19. A method for setup planning according to claim 16, wherein said setup constraints are identified by said identifying in accordance with the following:

20. A method for setup planning according to claim 16, wherein said identifying includes determining each of the setup constraints based on an intermediate shape of the part and a configuration of the tooling of the workstation for each operation.

21. A method for setup planning according to claim 20, wherein said determining includes providing a geometric model of the intermediate shape of the part and the configuration of the tooling, and calculating part-tool intersection regions to determine setup constraint parameters for each operation.

22. A setup planning system for generating a shared setup plan for operations to be performed by a workstation, said system comprising:

means for defining a family of parts;

means for identifying setup constraints imposed by operations to be performed on each part of said family of parts; and

means for generating a shared setup plan that satisfies all of the setup constraints that are identified for said family of parts;

wherein said generating means comprises;

means for determining, in accordance with the setup constraints that are identified, operations to be performed on said parts that have compatible setup constraints; and

means for assigning operations that are determined to have compatible constraints to corresponding tooling stages of the workstation to develop the shared setup plan for said family of parts;

wherein said determining means includes means for identifying a set of said operations that have compatible setup constraints by locating tooling stages that can accommodate each operation within said set of operations;

wherein each of the setup constraints comprises a set of setup constraint parameters, said setup constraint parameters defining setup constraints relating to the positioning of each part in the workstation to perform said operations; and

wherein said setup constraint parameters for each part comprise;

a gap length “

Gr”

on a right side of a bend position of the part, which denotes the distance by which a tooling stage can be extended towards the right side of the bend position;

a gap length “

Gl”

on a left side of the bend position of the part, which denotes the distance by which a tooling stage can be extended towards the left side of the bend;

an obstruction length “

Or”

on the right side of the bend position, which denotes a space in which no tooling is allowed on the right side of the bend position;

an obstruction length “

Ol”

on the left side of the bend position;

which denotes a space in which no tooling is allowed on the left side of the bend position;

a safety distance “

Sr”

on the right side of the bend position, which denotes a minimum distance between the bend position and a next tooling stage towards the right side of the bend position; and

a safety distance “

Si”

on the left side of the bend position, which denotes a minimum distance between the bend position and a next tooling stage towards the left side of the bend position.

23. A setup planning system according to claim 22, wherein said setup constraint parameters for each part include tooling parameters, at least one of said tooling parameters being defined according to a minimum tooling stage length for each operation that is given by:

24. A setup planning system according to claim 22, wherein said setup constraint parameters for each part include tooling parameters, at least one of said tooling parameters being defined according to a maximum allowed tooling stage length for each operation that is given by:

25. A setup planning system according to claim 22, wherein said setup constraints are identified by said identifying means in accordance with the following:

26. A setup planning system according to claim 22, wherein said identifying means includes means for determining each of the setup constraints based on an intermediate shape of the part and a configuration of the tooling of the workstation for each operation.

27. A setup planning system according to claim 26, wherein said determining means includes means for providing a geometric model of the intermediate shape of the part and the configuration of the tooling, and means for calculating part-tool intersection regions to determine setup constraint parameters for each operation.

28. A method for multi-part setup planning for bending operations to be performed by a workstation on a plurality of sheet metal parts in accordance with a composite setup plan, said method comprising:

defining a list O of operations to be performed on said plurality of parts; and

repeating the following until said list O is empty;

determining the most constraining operation o in said list O;

identifying a set of operations c(o) in said list O which have compatible constraints with said most constraining operation o;

defining a set of stages for the composite setup plan that satisfies the constraints for said most constraining operation o and said set of operations c(o);

assigning said most constraining operation o and said set of operations c(o) to the set of stages of the composite setup plan; and

removing said most constraining operation o and said set of operations c(o) from said list O.

29. A method for multi-part setup planning according to claim 28, wherein said determining comprises locating in said list O of operations a bending operation with a maximum bend line length, and assigning said bending operation with the maximum bend line length as the most constraining operation o in said list O.

31. A method for multi-part setup planning according to claim 28, wherein said identifying of operations with compatible constraints includes determining setup constraints for said list O of operations, each of the setup constraints comprising a set of setup constraints parameters that define setup constraints relating to the positioning of a part in the workstation to perform the bending operations.

32. A method for multi-part setup planning according to claim 31, wherein said setup constraint parameters include tooling parameters, at least one of said tooling parameters being defined according to a minimum tooling stage length for each operation that is given by:

33. A method for multi-part setup planning according to claim 31, wherein said setup constraint parameters include tooling parameters, at least one of said tooling parameters being defined according to a maximum allowed tooling stage length for each operation that is given by:

34. A method for multi-part setup planning according to claim 31, wherein said setup constraint parameters comprise:

a gap length “

Gr”

on a right side of a bend position of the part, which denotes the distance by which a tooling stage can be extended towards the right side of the bend position;

a gap length “

Gl”

on a left side of the bend position of the part, which denotes the distance by which a tooling stage can be extended towards the left side of the bend;

an obstruction length “

Or”

on the right side of the bend position, which denotes a space in which no tooling is allowed on the right side of the bend position;

an obstruction length “

Ol”

on the left side of the bend position;

which denotes a space in which no tooling is allowed on the left side of the bend position;

a safety distance “

Sr”

on the right side of the bend position, which denotes a minimum distance between the bend position and a next tooling stage towards the right side of the bend position; and

a safety distance “

Sl”

on the left side of the bend position, which denotes a minimum distance between the bend position and a next tooling stage towards the left side of the bend position.

35. A method for multi-part setup planning according to claim 34, wherein said setup constraints are determined in accordance with the following:

36. A method for multi-part setup planning according to claim 31, wherein said identifying operations with compatible constraints comprises determining that an operation I and an operation j are compatible when there exists a range of relative positions which satisfy the following:

37. A method for multi-part setup planning according to claim 31, wherein said identifying operations with compatible constraints comprises determining that a plurality of operations n are compatible when there exists a vector {X₁, X₂, . . . , X_n} which satisfies the following for every pair of operations i,j (where I does not equal j) of said plurality of bending operations n:

38. A method for multi-part setup planning according to claim 28, wherein said identifying operations with compatible constraints comprises locating tooling stages of the workstation that can accommodate each operation of said set of operations c(o) and said most constraining operation o.

30. A method for multi-part setup planning according to claim 40, wherein said determining comprises locating in said list O of operations a collinear bending operation with a maximum interruption index, and assigning said collinear bending operation with the maximum interruption index as the most constraining operation o in said list O.